In general, line testing is employed in wired communication networks for line testing of the respective communication lines. In such communication networks, terminal devices located in the premises of a customer (also referred to as subscriber) are connected with a central office via such communication lines. An example for a corresponding communication network is a public switched telephone network (PSTN) wherein terminal devices like telephones or facsimile devices are connected with the central office via a pair of copper lines. The copper lines are commonly referred to as tip line and ring line. In the recent years, data transfer services, such as integrated services digital network (ISDN) or digital subscriber line (DSL) (e.g., asymmetric digital subscriber line (ADSL)) have been employed over these copper lines, for example to provide access to the internet.
In such systems, in the central office the copper lines are usually connected with a subscriber line interface circuit (SLIC) on a corresponding line card which, depending on the services, is referred to as a PSTN line card, DSL line card, or the like.